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ADU Construction · St. Tammany County, Louisiana
Permit required
In Louisiana, a ADU Construction requires a building permit.
An accessory dwelling unit (ADU) always requires a building permit because it adds a habitable dwelling, including electrical, plumbing, mechanical permits and egress/zoning review. Plans are reviewed under the Statewide code (IRC 2021); apply through St. Tammany Parish Government- Permits & Inspections before work begins.
Source: Statewide, IRC 2021 · Verified 2026 by StateDataIndex
Building an Accessory Dwelling Unit requires complex zoning, structural, and utility permits.
With a population of around 272,421 residents, St. Tammany County generally runs a more streamlined permitting process than major urban hubs.
Code Compliance & Inspections
Because Louisiana sits in a hurricane-prone zone, the Louisiana Uniform Construction Code requires exterior work to use wind-rated materials and proper anchoring (such as tie-downs and impact-rated components) to pass inspection.
Concurrent Permits & HOAs
For St. Tammany County residents, we highly recommend reviewing your neighborhood HOA covenants before paying any municipal fees. Often, homeowners associations maintain stricter rules regarding materials and dimensions for your ADU Construction than the county itself.
Zoning & Cost Factors
Louisiana zoning is heavily influenced by parish (county) governments, with critical oversight on flood elevations and coastal rebuilding codes. Fortunately, Louisiana maintains relatively builder-friendly regulations, keeping base permit fees competitive.
Permit fees in St. Tammany County
Permit fees vary by jurisdiction and by your project's valuation, so there is no single fixed figure for St. Tammany County. We only publish fees confirmed by real homeowners — none have been reported here yet.
Confirm the current fee directly with St. Tammany Parish Government- Permits & Inspections ((985) 898-2574). If you have paid for a permit here, you can add it here to help others.
St. Tammany County Building Department
Office: St. Tammany Parish Government- Permits & Inspections
Address: 21454 Koop Dr #1b, Mandeville, LA 70471, USA
Phone: (985) 898-2574
Source: official St. Tammany County government records. Hours and procedures can change — call ahead to confirm.
How to Apply in St. Tammany County
In St. Tammany County, you or your contractor typically submit blueprints and a property survey to the local building department. Call ahead to confirm hours and accepted payment methods.
ADU Construction Requirements in St. Tammany County
Typical Submittal Package
When applying for a ADU Construction permit, you or your contractor will generally need to submit the following documentation for the city's review:
- Comprehensive architectural and structural plans
- Foundation engineering reports
- Sewer, water, and utility connection plans
- Site plan showing property lines and setbacks
Standard Ordinances & Processing Time
Key code points for a ADU Construction in St. Tammany County: ADUs typically have maximum square footage limits (often 800-1200 sq ft), height restrictions, and usually require dedicated off-street parking depending on local zoning.
Typical processing time for a jurisdiction of this size: 2 to 4 weeks.
Frequently Asked Questions
What are the specific penalties for unpermitted ADU Construction work in urban St. Tammany County?
Building without authorization is considered a code violation. The local government can issue a Stop Work Order, forcing you to halt construction immediately. You may be subject to retroactive permit fees (often double the original cost), daily fines, or even a mandate to tear down the unpermitted work at your own expense.
Can a homeowner pull their own ADU Construction permit in Louisiana?
Yes. Louisiana generally allows property owners to act as their own general contractor under an Owner-Builder exemption. If you take this route, you assume full legal and financial liability and must ensure all work complies with the Louisiana Uniform Construction Code.
How much does a ADU Construction permit cost in St. Tammany County?
Permit fees vary by jurisdiction and by your project's valuation, so St. Tammany County does not publish a single fixed figure. Confirm the exact fee with the local building department before applying.
How long does it take to get a ADU Construction permit in St. Tammany County?
Based on the size of St. Tammany County, the typical processing time is 2 to 4 weeks. Times vary with the season and the building department application volume.
Where do I apply for a ADU Construction permit in St. Tammany County?
You can apply through the St. Tammany Parish Government- Permits & Inspections or online via the county permit portal. For questions, call (985) 898-2574.
Help the St. Tammany County Community
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Read GuideBuilding It Yourself? Here's What You'll Need
Planning an ADU? Tools homeowners use in the design and layout phase:
📘
Backyard ADU Design Guide (Book)
View on Amazon →
📐
Laser Level
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🔍
Franklin ProSensor Stud Finder
View on Amazon →
📏
25ft Tape Measure
View on Amazon →
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Other Permit Types in St. Tammany County
Planning another home improvement project? Check the requirements and fees for:
Nearby Jurisdictions in Louisiana
Building near the county line? Check requirements for neighboring areas: